Surebet Calculator (Arbitrage Betting)

Updated: 16.09.2026

The surebet calculator determines whether an arbitrage situation exists between the odds of different bookmakers. Enter the odds for every outcome and the total stake — the calculator will show whether a surebet exists, work out the optimal stake distribution and the guaranteed profit.

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What is a surebet in betting

A surebet (arbitrage bet) is a situation where the odds offered by different bookmakers allow you to back every outcome of an event and lock in a profit regardless of the result. A surebet exists when the sum of the reciprocal odds (implied probabilities) across all outcomes is less than one.

For example, one bookmaker offers 2.10 on the home win while another offers 2.10 on the away win. The sum 1/2.10 + 1/2.10 = 0.952 is below 1, so a surebet exists. With the stakes distributed correctly, you earn roughly 4.8% of the total staked, no matter how the match ends.

Surebets appear because of differences in bookmakers’ assessments. Each bookmaker compiles its lines independently, and on some events their odds can diverge enough to create an arbitrage opportunity. Such situations are usually short-lived — from a few minutes to a couple of hours.

Bookmaker surebets: how arbitrage situations arise

Let’s look at an example. A football match: Team A vs Team B. One bookmaker rates Team A higher and prices its win at 2.15; another sees it differently and offers 2.10 on Team B for the same match. Check: 1/2.15 + 1/2.10 = 0.465 + 0.476 = 0.941. The sum is below 1 — a surebet with a 5.9% margin.

The main reasons surebets appear: lines being updated at different speeds after the news (injuries, line-ups), differences between bookmakers’ statistical models, manual line adjustments by traders. In practice surebets with a margin above 3% are rare; typical values are 1–2%.

Surebet calculation formula

To determine whether a surebet exists, add up the reciprocals of the odds on all outcomes. If the sum is less than 1, a surebet exists.

Checking for a surebet (2 outcomes):

1/O₁ + 1/O₂ < 1 → surebet exists

For three outcomes (1X2):

1/O₁ + 1/Ox + 1/O₂ < 1 → surebet exists

Arbitrage margin (surebet yield):

Margin = (1 − (1/O₁ + 1/O₂)) × 100%

Stake distribution for outcome i:

Stake_i = Total × (1/O_i) / (1/O₁ + 1/O₂)

Example: odds of 2.10 and 2.10 on two outcomes, total stake $10,000.

  • Sum of probabilities: 1/2.10 + 1/2.10 = 0.476 + 0.476 = 0.952
  • Surebet margin: (1 − 0.952) × 100% = 4.76%
  • Stake on outcome 1: 10,000 × 0.476 / 0.952 = $5,000
  • Stake on outcome 2: 10,000 × 0.476 / 0.952 = $5,000
  • Return on any outcome: 5,000 × 2.10 = $10,500
  • Profit: 10,500 − 10,000 = $500

How to find surebets

Searching for surebets manually is a laborious process: you need to compare the odds of several bookmakers on the same event. In practice several approaches are used:

  • Comparing lines — open the markets for one event at several bookmakers and compare the odds on opposite outcomes.
  • Dedicated scanners — automated surebet services scan the lines of dozens of bookmakers and show arbitrage situations in real time.
  • Pre-match vs live — surebets appear more often in live betting, when bookmakers fail to synchronise their odds after goals or other events.
  • Lower leagues — on less popular events the spread of odds is wider, so arbitrage situations occur more often.

To check a specific situation, use the margin calculator — if the margin is negative, you are looking at a surebet.

Surebet scanners vs manual search: which works better

Manual surebet hunting requires monitoring the lines of 5–10 bookmakers simultaneously. In practice this takes hours and yields 1–3 surebets a day. Scanners automate the process: they monitor dozens of bookmakers and surface arbitrage situations within seconds.

Bear in mind that paid scanners (BetBurger, OddStorm, RebelBetting) cost between €50 and €150 a month. With an average surebet margin of 1.5% and a bankroll of $5,000 you would need to find and play 8–10 surebets a day just to cover the subscription. Free scanners show surebets with a 30–60 second delay, during which the situation often disappears.

Risks of arbitrage betting

Arbitrage betting is often presented as risk-free earnings, but in practice it comes with significant limitations and risks:

  • Account restrictions — bookmakers track players who systematically bet on surebets. The result is slashed maximum stakes and account closure. This is common practice at licensed bookmakers.
  • Odds changes — while you are placing the bet with the second bookmaker, the odds may move. One “leg” of the surebet is already placed, and the other has become unprofitable.
  • Voided bets — a bookmaker may void a bet on technical grounds (palpable error in the odds). The other half of the surebet remains in place.
  • Withdrawal delays — during account verification or bet reviews, payouts can be held up for days or weeks.
  • Low yield — a typical surebet margin is 1–5%. Once deposit and withdrawal fees are factored in, the real profit can be minimal.

Remember that sports betting involves financial risk. Follow bankroll management principles and only stake money you can afford to lose.

Live and pre-match surebets: where the opportunities are

Pre-match surebets appear less often — bookmakers have time to synchronise their lines. The margin on such surebets is usually 0.5–2%. On the other hand they are more stable: odds drift slowly and there is time to place both bets.

Live surebets occur more frequently — after goals, red cards or injuries bookmakers update their lines at different speeds. The margin on live surebets can reach 5–10%, but the window for placing the bets is 10–30 seconds. The risk is higher: the odds can change between the first and the second bet, turning the surebet into a losing position. For live surebets, connection speed and the ability to work with several sites at once are critical.

Over a run of 100+ surebets the variance is minimal — each bet returns a fixed percentage of profit. However, a surebet’s success rate (the share where both legs are placed in time) depends on speed: with a delay, the odds on the favourite or the underdog can shift, and instead of a surebet you end up with an ordinary bet with a negative expectation.

Other calculators

Further reading: Advanced Betting Strategies — arbitrage theory and a mathematical approach to betting.

Frequently asked questions about arbitrage betting
🙋 What is a surebet in sports betting?
💁 A surebet is a situation where the odds offered by different bookmakers on opposite outcomes allow you to bet in such a way that you profit whatever the result. A surebet exists if the sum of the reciprocal odds (1/O₁ + 1/O₂) is less than one.
🙋 How do I calculate the stakes for a surebet?
💁 Split the total amount in proportion to the reciprocal odds. The formula for each outcome: Stake = Total amount × (1/Odds) / Sum of all (1/Odds). This guarantees an equal return whatever the result.
🙋 What percentage of profit do surebets bring?
💁 A typical surebet yields 1–5% of the amount staked. Surebets yielding more than 10% are rare and usually stem from an error in a bookmaker’s line, which may be voided.
🙋 Is arbitrage betting legal?
💁 Arbitrage betting is not against the law. However, bookmakers are entitled to restrict players who systematically use surebets — lowering maximum stakes or closing the account in line with the company’s rules.
🙋 Can a surebet exist at a single bookmaker?
💁 In theory, yes, if the bookmaker has made a mistake in its line. In practice this is extremely rare, as bookmakers automatically control their margin. Surebets usually arise between different bookmakers with differing probability assessments.
🙋 What is the difference between a surebet and hedging?
💁 A surebet involves simultaneous bets on all outcomes with different bookmakers to lock in a profit. Hedging is a bet on the opposite outcome placed after the first bet, to secure a profit or cut losses. To work out a hedge, use the hedging calculator.